In general, a multicast broadcast service (hereinafter referred to as MBS) is a point-to-multipoint service in which data is transmitted from a single source to a plurality of recipients. In the MBS, a common resource is used to efficiently use a wireless resource and a wire resource. The MBS is a unidirectional service.
In particular, in a wideband wireless access network that is a field of a mobile communication system, in order for a plurality of recipients to commonly use a resource, a CID (Connection ID) that is an identifier of packets that are transmitted through a wireless channel is defined as a multicast CID (hereinafter, mCID). If a plurality of mobile terminals that receive a multicast service share the mCID, the plurality of mobile terminals can receive multicast packets.
Here, the MBS is classified into two types according to structures of cells. One is a single base station (BS) connection method in which a single BS only transmits multicast packets. The other is a multi-BS connection method in which a plurality of BSs simultaneously transmits the same packet.
In the multi-BS connection, a group of BSs that simultaneously transmit the same packet is defined as a multicast broadcast service zone (MBS zone). A plurality of mobile terminals in one MBS zone has the same mCID regardless of whether the mobile terminals are activated or not. Even if the BS is changed, the mobile terminals can receive multicast packets without being registered again in a new BS through the mCID. However, the MBS is only provided in a downlink and an ARQ (Automatic Repeat Request) is not applied.
Further, in order to provide the MBS to the mobile terminals in the wideband wireless access network, a control procedure and a transmission method of providing the MBS between constituent elements need to be defined. Messages and parameters in the wireless channel are already defined by IEEE 802.16e. In order to provide the MBS, a message function and a message processing method need to be defined again. Since messages and parameters in a wire channel are not standardized, it is required to standardize the messages and parameters in the wireless channel.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.